sound cutting off in 7

A strange problem has suddenly developed on my system. I had been playing with version 7.0.3 without problem since it's been available. However, the last 2 times 
I turned it on, the sound cuts off abruptly after a few minutes of playing . The only cure is to quit and open again.
But it systematically does the same thing every time. I upgraded to 7.0.5, but the problem occurs just the same. Absolutely nothing has changed in my system:
Mac mini 2012 quad core, 16 MB ram
Cambridge DAC magic
macOS 10.13.6 High Sierra
settings: 48KHz, 128 samples buffer, 96 notes polyphony

Like I said, it performed perfectly well up to now, playing flurries of notes with liberal pedal for hours...
Au secours! mayday, sos 

EDIT: looks like the problem came from the DAC having a conflict with the Apple audio midi set up. Resetting everything seems to have solved the problem.Fingers crossed...